Aside from the usual native networks...
Revcontent, MGID, Content-Ad, Taboola and Outbrain...
What other sources can run Nutra type offers/ads/landers?
There are quite a few of them out now 
You listed some and here is more for you to check out :
adnow
gravity
nativeads
earnify
adblade
adyoulike
revenue.com
nativo
triplelift
payclick
adsupply
plugz
adsnative
sharethrough
ayboll
soutable
mediavenus
...
Can't really comment on their traffic quality, you have some testing ahead 
We at ActiveRevenue have some great Hige quality WW Nutra sources, Skype: Tal_740
hey tal, sorry to hijack this thread, let's get in touch we can try to get something going together.
Hey, I would like to recommend our company, Mandatory.io, our account managers can help you make the best Native Nutra-based campaigns for you from our direct publisher's traffic.
Lets chat
Skype: bsgies
Hello there!
We have some good performances for that vertical in Adnow;
Poland, France, Romania, Brazil, Italy, and Russia are booming now! The volumes have grown substantially, I highly recommend to check them out.
Other “juicy” GEOS that might interest you: Thailand, Greece, UK, India, Argentina, Georgia!
Get in touch via Skype if you'd like to have more: asemeano
Separate shoutout to guys from MGID. Tight moderation but great traffic!
Hi, the traffic depends on the geo you want to advertise in. Adnow has great potential if you are willing to utilize the blacklisting tools. MGID is extremely difficult to manage, but also offers great traffic.
There is also something to be said about small, local networks. I used to work in Bulgaria with EasyAds and Adwise, in Poland with ContentStream, and results can be great.